Recently in the semiconductor industry, EUV lithography, which is an exposure technology that uses extreme ultraviolet (EUV) light, is considered to be promising accompanying the miniaturization of semiconductor devices. EUV light refers to light of a wavelength band of the soft X-ray region or vacuum ultraviolet region, and more specifically, refers to light having a wavelength of about 0.2 nm to 100 nm. Examples of transfer masks proposed for use in this EUV lithography include the reflective exposure mask described in Patent Literature 1 (JP-A-2002-246299) and the reflective photomask described in Patent Literature 2 (JP-A-2010-192503).
On the other hand, miniaturization of transfer patterns formed on light shielding layers has become remarkable in recent years even in the case of binary masks used in lithography using an ArF excimer laser for the exposure light source. The direct formation of a transfer pattern by using a resist pattern of an organic material as a mask and carrying out dry etching on a light shielding layer is becoming increasingly difficult. As means for solving this problem, etching mask films of metal-based materials (hard masks) as described in Patent Literature 3 (JP-A-2006-78807) have come to be applied.